Re-reading 4.1.5.5 and comparing with older versions, I feel that the requirement
of keeping old header field values "as-is", so that they can be re-instated via a
simple copy is no longer explicit.
Thus,
"When forwarding an HTTP request with altered HTTP header fields, in addition
to complying with the rules of normal HTTP operation, proxies must include in
the request copies of the unaltered header field values in the form
"X-Device-"<original header name> so that it is possible to reconstruct the
original header field values."
becomes
"When forwarding an HTTP request with altered HTTP header fields, in addition
to complying with the rules of normal HTTP operation, proxies must include in
the request additional fields in the form "X-Device-"<original header name>
whose values are verbatim copies of the corresponding unaltered header field
values, so that it is possible to reconstruct the original header fields."
Apart from this, I do not see anything more to adjust in
the text.
E.Casais